The special constable murdered by her husband helped him run a brothel and used her position to recoup unpaid bills from prostitutes' clients.

According to police files, Nisha Patel-Nasri, 29, and husband Fadi Nasri went to the home of one client in a dispute over a £700 debt.

Once there, she showed her warrant card and claimed to be on official business.

Nisha with husband Fadi Nasri on their wedding day. She became deeply embroiled in his seedy business affairs

Nisha with husband Fadi Nasri on their wedding day. She became deeply embroiled in his seedy business affairs

The incident led to her being reported to a Metropolitan Police anti-corruption unit by a fellow officer.

It was also reported to detectives investigating her killing.

Dave Eden, of Hertfordshire Police, said he had responded to a 999 call from an escort agency client in Elstree in 2003.

The client said Mrs Patel-Nasri, Nasri and others had tried to force their way into his house. He also alleged she had previously supplied him with cocaine at &pound;50 a gram.

When Sgt Eden arrived, Mrs Patel-Nasri told him she had only used her warrant card as identification.

Sergeant David Eden made a complaint to Scotland Yard about Nisha's behaviour

Sergeant David Eden made a complaint to Scotland Yard about Nisha's behaviour

He said in a statement after her death: 'She was very aggressive. She told me that I had no idea who I was ****ing dealing with - that I was a county force sergeant and her powerful friends at Scotland Yard could have me out of a job.

'She advised me that my officers and I withdraw from the scene and allow them to get on with their business if I knew what was good for me.'

It has also emerged that a prostitute-who worked for escort agency Seventh Heaven, which was run by Nasri, told murder detectives that Mrs Patel-Nasri had helped run the business and drove call girls to jobs.

Maria Brennan added: 'Nisha used to ring me up all the time and tell me I had to work, otherwise I was losing her money . . .

'I was aware Nisha had apparently used her police badge to recover debts and I was aware of being violent towards clients.' Details of the allegations are in police files, parts of which were read to the court during 34-year-old Nasri's trial.

He was found guilty of murder at the Old Bailey last week after a jury heard he paid two hitmen £18,000 to kill his wife so he could claim her £350,000 life insurance and start a new life with Lithuanian prostitute Laura Mockiene.

Drug dealer Roger Leslie, who arranged the killing, and knifeman Jason Jones were also convicted of murder.

Mrs Patel-Nasri, who became a special constable with the Met in late 2002, was stabbed to death on the doorstep of her home in Wembley, North London, in May 2006.

The £700 debt incident was investigated and Mrs Patel-Nasri was verbally warned 'for using her warrant card for enforcing civil debts'.

Scotland Yard said it was concluded that no criminal offence had been committed.

Commander Rod Jarman, of the Metropolitan Police, said: 'The reputation Nisha had with friends, colleagues and family is one of a hard-working, loving individual who gave her time for the good of the community and it is this I believe should be remembered.'